Apparatus for assembling shell molds



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April 9, 1957 w. E. MILLAGAN APPARATUS FOR ASSEMBLING SHELL MoLDs Filed Feb. 2o, 1953 Filed Feb. 20, 1953 April 9, 1957 W. E. MILLIGAN APPARATUS FOR ASSEMBLING SHELL MOLDS 6 Sheets-Sheet 2 IN V EN TOR. Malayan.

- Hfs' Amfomvry April 9, 1957 w. E. MILLIGAN 2,787,814

APPARATUS FOR ASSEMBLING SHELL MOLDS Filed Feb. 20, 1953 6 Sheets-Sheet 3 IN VEN TOR.

H15 TTOHNE' Y April 9, 1957 w. E. MILLIGAN 2,787,814

APPARATUS FOR ASSEMBLING SHELL MOLDS Filed Feb. 20, 1953 6 Sheets-Sheet 4 INVENTOR.

WS ATTORNEY April 9, 1957 w. E. MILLIGAN 2,787,814

APPARATUS FOR ASSEMBLING SHELL MOLDS Filed Feb. 20, 1953 6 Shleets-Sheet 5 mq w TH: w Q@ N N m l I n 5 l@ m l@ o i @S L r 'Q Q INVENTOR. 1 w w .L Wam@ Emzagm.

MS TTOHAY l April 9 1957 w. E. MILLIGAN 2,787,814

APPARATUS FOR ASSEMBLING SHELL MOLDS Filed Feb. 20, 1953 6 Sheets-Sheet 6 HIS TTOBNE Y APPARATUS FR ASSEMBLING SHELL MLDS Wilbur E. Milligan, Quincy, Mass., assigner to Walworth Company, Boston, Mass., a corporation of Massachusetts Application February 2t), 1953, Serial No. 338,045

Claims. (Cl. 22-31) This invention relates to casting methods and apparatus and more particularly to metho-ds and devices for assembling matching sections of shell-type molds.

Shell molds are comprised of a major portion of an inorganic molding material, such as sand, and a minor portion of a component serving to bind the inorganic material. The completed molds are in two or more matching parts having the form of hard, thin shells of substantial strength. The inner faces of the matching parts are smooth and linished whereas the outer surfaces are left in a rough and irregular condition. Consequently during the casting operation using such molds, the usual casting methods for ordinary sand molds cannot be used with any degree of success.

In casting operations using shell-type molds, it has been customary to embed the mold parts in a loose relatively coarse granular material in `a casting box with the intention of enabling the mold to withstand the static pressure of the molten metal. Refractory materials, such as steel shot, sand and gravel have been proposed as suit-able bedding material to be contained in the pouring box. It is dillicult, however, to support the two halves of the mold in proper position within the casting box while the refractory material is loaded around the same. It has been found that this difficulty may be largely overcome and the mold sections maintained in correct orientation relative to each other if the inner faces of the matching parts are cemented together, preferably by a thermosetting adhesive, before the assembled mold is placed in the casting box.

lt is a principal object of this invention to Iassemble the mold sections into a unitary mold adapted for insertion into the casting box.

Another object of this invention is to simplify the assembly of matching mold sections so that a single operator may produce a. large quantity of assembled molds.

Another object of this invention is to form a unitary moldby cementing matching mold sections together.

Another object of this invention is to automatically move assembled mol-ds from an operators station through a heated zone to set the mold cementing agent and thereafter return the assembled molds to the operators station.

The device for accomplishing these and other objects and advantages of the invention comprises a rotatable support or conveyor which carries a plurality of clamping units adapted to hold a number of pairs of matching mold sections together. Movement of the conveyor carries assembled molds-from an operators station through a zone maintained at elevated temperatures and returns the assembled mold sections to the operators station for removal from the conveyor.

. Other objects and advantages will become apparent from the following specification taken in connection with the accompanying drawings wherein:

Fig. lis a side elevation of a mold assembling device embodying this invention;

I Fig. 2 is a view taken on the line I--II of Fig. 1;

rates Patent rice Fig. 3 is a cross-section taken on the line III-lll of Fig. 1;

Fig. 4 is a cross-section of a detail shown 4on an enlarged scale;

Fig. 5 is a plan view of the detail shown in Fig. 4;

Fig. 6 is a cross-section taken on the line VI--VI of Fig. 2;

Fig. 7 is a fragmentary side elevation taken on the line Vif-VII of Fig. 2 and shown on an enlarged scale;

Fig. 8 is a fragmentary view taken on the line VIII-VIII of Fig. 6 and shown on an enlarged scale;

Fig. 9 is a view taken on the line lX-IX of Fig. 1 and shown on an enlarged scale;

Fig. 10 is a plan view of another embodiment of the invention; and

Fig. 1l is a side elevation of the apparatus shown in Fig. l0.

Referring more particularly to Figs. 1 9 of the drawings, the mold assembling device comprises a rotatable support or conveyor 10 having a plurality of clamping devices 12 arranged around the periphery thereof, each of the clamping devices 12 being adapted to carry an assembled pair of mold sections. The conveyor 16 cornprises an elongated framework of polygonal, here shown as rectangular, cross-section Idefining Ia plurality, in this instance four, of circumferentially spaced supporting frames 14. The clamping devices 12 are respectively mounted on the supporting frames 14 and the conveyor or framework 10 is pivotally mounted on a supporting structure 16 so that rotation of the conveyor lil about its pivot will move the clamping devices 12 through a predetermined path.

Means is provided for heating a zone adjacent the conveyor 10 so that rotation thereof will move the clamping devices and assembled molds carried thereby through the heated zone. To this end, a heater 17 is mounted on the supporting structure 16 and positioned adjacent the conveyor 10.

The clamping devices 12 are best shown in Figs. l, 2 and 6 and, since all these devices are identical, a description 0f one will sufce to disclose the construction of all. Each clamping device 12 comprises rst abutment means supported on one of the frames 14 of the conveyor lll, which means takes the form of a plurality of spaced yieldable elements adapted to engage the edge portion of a mold section placed thereon. More specifically, four structural members such as angles 18 are secured at their ends by welding or the like and are arranged generally in the shape of a rectangle. Each angle 13 has a pair of C- clamps 22 slidably mounted thereon for axial adjustment relative thereto. A set screw 24 is threaded into each clamp 22 and cooperates with the associated rangle l for restraining relative movement between the angle and clamp so that each clamp 22 may be positioned at any selected point on its supporting angle i3.

Each set screw 2d is provided with an elongated cylindrical head adapted to be telescoped within a coil spring 26. Each spring 26 is retained on its associated set screw head by a pin 2S extending through the set screw head and projecting between contiguous turns of the spring 26. The springs 26 extend beyond the set screws 24 and thus define a plurality of yieldable abutments engageable with the edge portion yof a mold section placed thereon.

As best shown in Fig. 6, a rst mold section 34 (shown in broken lines) placed on the springs 26 will be in position for cleaning and application of adhesive to the surfaces which are to engage the second mold section 36. in operation, an operator rst places the first mold section 34 on the springs 26, cleans the mold section, applies adhesive to the surfaces which are to engage the other mold section 36 and then places the other mold section 36 on the first mold section 34. To insure correct orienta tion of thc two mold sections, registering recesses are usually formed in the matching faces thereof for the reception of a dowel element of core material or the like or complementary registering recesses and bosses may be formed in the mold sections respectively. After the mold sections are assembled, second abutment means are moved into engagement with the top mold section 36 to thereby clamp the mold sections together.

This second abutment means takes the form of a plurality of yieldable elements 38 mounted on four shafts 40, 41, 42, 43 rotatably mounted on suitable brackets 39 carried by the frames 14 of the conveyor 1t). As best shown in Fig. 2, the shafts 40, 41, 42, 43 are arranged in the form of a rectangle and are connected at their ends through a plurality of bevel gea-rs 44. The shafts 40, 41, 42, 43 are here shown as being interconnected through four right angle bevel gear units 46 of the type sold under the trademark ANGL GEAR.

At least one yieldable element 38 is carried on each of the shafts 40, 41, 42, 43 and a plurality, in this instance two, of these elements is carried on each shaft. As best shown in Figs. 6 and 8, each yieldable element 3S cornprises a collar 47 keyed to the shaft 40/41/42/43 and provided with a laterally extending arm 48 the end portion S6 of which is offset and extends axially of the supporting shaft. A lever 52 is loosely pivoted on the supporting shaft contiguous the collar 47 with one end 54 thereof overlying the offset end portion 50 of the arm 48. The end S4 of the lever S2 is bifurcated and straddles the shank of a bolt 56 carried by the offset portion 50 of the arm 48, the head S8 of the bolt 56 being engage able with the end 54 of the lever 52 to limit pivotal movement of the lever 52 about its supporting shaft. A spring 60 carried on the bolt 56 acts between the arm 48 and the end 54 of the lever 52 to bias the latter toward the head S8 of the bolt 56. The other end 62 of the lever' 52 is arranged to extend over the edge portion of the assembled mold section 34, 36 when the same are supported on the springs 26.

Movement of the yieldable elements 38 into and out of engagement with assembled mold sections supported by the springs 26 is effected by an operating lever or handle 64 secured to an extension 65 of the shaft 40 and adapted to be manually operated to -rotate the same in the bearings of the bevel gear units 46.

Associated with the handle 64 and as best shown in Figs. 2 and 7, is a latching mechanism adapted to lock the handle 64 in a first position wherein the yieldable clamping elements 38 are in engagement with the assembled mold sections S6, 34 and to release the handle 64 for movement to a second position (as shown in broken lines in Fig. 7) wherein the yieldable elements 38 are free of the assembled mold sections.

The latching means comprises a ratchet wheel 66 secured by welding or the like to one of the brackets 39 and having a central aperture 68 through which the extension 65 of the shaft 40 extends. A click or ratchet 70 is carried in a suitable bracket 72 which is secured to the handle 64 for movement therewith. Spring means (not shown) bias the ratchet 70 toward the ratchet wheel 66 and a Vfinger receiving ring 74 is formed on the end of the ratchet 70 to provide a hand-hold for moving the ratchet '70 against it bias.

ln operation, movement of the handle 64 from the broken line position of Fig. 7 to the full line position shown therein, will cause counterclockwise movement of the shaft 46 to move the clamping elements 38 carried thereby into engagement with the top mold section 36 and compress the springs 60 of the clamping elements 38, the ratchet 70 moving over the periphery of the ratchet wheel 66 during such movement. It will be apparent that the springs 60 will tend to bias the shaft 40 in a clockwise direction as viewed in Fig. 7 but movement under this bias will be prevented by engagement of the ratchet with the ratchet wheel 66. The rotational movement thus imparted to the shaft 40 will be trans mitted through the right angle bevel gear units 46 to the shafts 41, 42 and 43 respectively, causing the satne to rotate in such directions as to bring the clamping elements 38 carried thereby into engagement with the top mold section 36.

When it is desired to release the clamping elements 38 from the assembled mold sections 34, 36, the ratchet 70 is moved against its bias out of engagement with the ratchet wheel 66 and the handle 64 is moved to the broken line position as shown in Fig. 7. Such movement of the handle 64 transmits a clockwise movement (as viewed in Fig. 7) to the shaft extension 65 and shaft 40 to lift the clamping elements 38 carried by the shaft 40 away from the mold section 36. Similar movement will be transmitted through the right angle bevel gear units 46 to the shafts 41, 42 and 43 respectively to move all the clamping units 38 out of engagement with the mold section 36.

The pivotal mounting of the conveyor 10 comprises a shaft located axially thereof and journaled in a pair of bearings 82. The bearings 82 are respectively secured to a pair of spaced parallel columns 84 extending vertically from a horizontal supporting platform 86.

Means is provided for rotating the conveyor 1.0 about the axis of the shaft 80 in sequential increments or indexed steps. As here shown, the conveyor actuating mechanism comprises a rack 8S mounted for vertical reciprocable movement on one of the columns 84 and meshing with a quadrant gear loosely mounted on the shaft 80 adjacent a ratchet wheel 92 which is keyed to the shaft S0. Movement of the ratchet wheel 92 is normally prevented by a pair of pawls 94, 96 pivoted on the bearing 82 and arranged to engage the ratchet wheel 92, the pawl 94 preventing clockwise movement and the pawl 96 preventing counterclockwise movement as viewed in Fig. 4.

Movement is transmitted from the quadrant 90 to the ratchet wheel 92 by a ratchet or click 97 which is pivoted on the quadrant 90 and arranged to engage the ratchet wheel 92 for moving the same in one direction. To release the pawl 94 and thereby permit the ratchet 97 to actuate the ratchet wheel 92, a pin 98 extends laterally from the ratchet 97 to be engageable with a boss 100 formed on the pawl 94. The boss 100 is so constructed that it will be contacted by the pin 98 to release the pawl 94 before a driving connection is established between the ratchet 97 and the ratchet wheel 92 upon clockwise (as viewed in Fig. 4) movement of the quadrant 90. However, upon reverse movement of the quadrant 90, the pin 98 will ride over the boss 100 to urge the pawl 94 toward the ratchet wheel 92 to securely latch the same.

Actuation of the rack 88 is effected through a suitable fluid pressure operated piston motor 102 mounted on the column 84 and connected by suitable linkage 104 to the rack 88. ingress and egress of fluid under pressure to the motor 102 is under the control of a suitable foot actuated switch 106 through any suitable electrically operable valve and connections (not shown).

Referring to Figs. 1 and 4, the rotation and indexing of the frame 10 may be described as follows:

Fluid under pressure is admitted to the motor 102 to move the rack 88 downward thereby imparting c1ock wise rotation to the quadrant 90 to move the pin 98 on the ratchet 97 into engagement with the boss 100 to thereby move the pawl 94 in a counterclockwise direction about its pivot and out of engagement with the ratchet wheel 92. Further rotation of the quadrant 90 will bring the ratchet 97 into driving engagement with the ratchet wheel 92 to move the same in a clockwise direction thereby rotating the shaft 80 and the frame 10 supported thereby. Such further rotation also serves to move the pin 98 out of engagement with the boss @rusia 100 thereby permitting the pawl 94 to drop into engagement with the ratchet wheel 92.;

Upon completion of its stroke, the motor 102 returns the rack 88 to its initial position thereby rotating the quadrant 90 in a counterclockwise direction to its initial position. During such return movement of the quadrant 90, the pin 98 rides over the top of the boss 100 which has moved downward with the pawl 94 as the same dropped into engagement with the ratchet wheel 92.

In the embodiment of the invention shown in Figs. 1-9, one of the supporting surfaces 1d is disposed at approximately 30 to the horizontal when the frame 1d is in its indexed position with the pawls 94, 96 in engagement with the ratchet wheel`92. Such positioning of the supporting surface 14 and clamping device 12 carried thereby facilitates insertion and removal of mold sections by an operator. When each clamping device 12 is so located, it is said to be in the loading station which is indicated in Fig.'l ofthe drawings by the reference charactery A. It rrwill beA apparent that sequential operation of the Vswitch 106 will cause each of the clamping devices 12 to be positioned sequentially at the loading station A.

The heater 17 for heating a zone (indicated by the reference character B) adjacent the conveyor 10 is here shown as comprising a burner 108 carried on a pivotal support 110. The support 110 includes a pair of elongated trunnions 112 journaled in a pair of bearings 114 which are supported by a pair of cantilevers 116 extending from the columns 84 respectively. Means is provided for swinging the burner 108 away from the frame 10 and to this end a lever 120 is secured at one end to the burner support 110 and is pivotally connected at the other end to a piston 122 of a fluid pressure actuated motor 124. The motor 12d is pivotally connected to a brace 126 extending between the columns 84 so that reciprocation of the piston 122 will cause the burner 108 to swing toward and away from the conveyor 10.

Flow of motive fluid to and from the motor 12dis controlled by the foot switch 106 through any suitable electrically operable valve and connections (not shown) so that the burner 108 is moved away from the conveyor 10 to the broken line position shown in Fig. l during the first half of an indexing operation as hereinbefore described, and is returned to its initial position upon completion of the indexing operation. This arrangement permits the burner 108 to be positioned proximate assembled mold sections held by a clamping device 12 when the same is in the heated zone B but permits adequate clearance for rotation of the frame 110.

The swinging burner 108 is supplied with fuel through a flexible conduit 128 connected thereto and to a source of fuel supply (not shown).

In operation, a first mold section is placed on the springs 26 at the loading zone A where it is cleaned and coated with a thermosetting adhesive. A matching mold section is then placed upon the first mold section and the yieldable clamping elements 38 are moved into engagement therewith to securely clamp the mold sections together. The switch 106 is then operated to admit fluid under pressure to the pressure motor 102 to move the assembled mold sections into the heated zone B while at the same time moving a completely assembled mold section into the loading station A where it may be easily removed by an operator. Fluid under pressure is also admitted to the motor 124 to move the bunrer 108 to the broken line position (Fig. 1) during indexing.

The assembled mold remains in the heated zone B and the thermosetting adhesive sets up to unite the matching mold sections while the loading operation is repeated at the loading station A. Upon a second indexing operation, the bonded sections are moved out of the heated zone B and, after subsequent indexing operations are returned to the loading station A for removal.

It is to be noted that while the assembled mold is in the heated zone'B', only one of the mold sections is exposed directly to the source of heat. It has been found that such an arrangement has the particular advantage of preventing scorching of the sections and producing a stronger bond therebetween.

The modified construction illustrated in Figs. 10 and 1l, in which like numerals designate corresponding parts, is a departure from that shown in Figs. l-9 in that the conveyor 10 is rotatable about a vertical axis with the supporting frames 14 formed thereon being maintained at 45 to the vertical at all times. f

The embodiments of the invention herein shown and described are to be regarded as illustrative only, and it is to be understood that various modifications and changes may be made within the scope of the appended claims without departing from the spirit of the invention.

It is claimed and desired to secure by Letters Patent:

l. Apparatus for assembling matching sections of shell-'type molds comprising a hollow frame, yieldable means carried by said frame and adapted to engage the outer edge portions of a mold section positioned within said frame for supporting the same to receive another moid section in superimposed relation, a plurality of clamping members, movable means carried by said frame for supporting said clamping members in spaced arrangement around said frame, and means for actuating said movable means to position said clamping members for operative engagement with the outer edge portions of said other mold section in said superimposed relation.

2. Apparatus for assembling matching sections of shell-type molds comprising a polygonal hollow frame, yieldable means carried by said frame and adapted to engage the outer edge portions of a mold section positioned within said frame for supporting the same to receive another mold section in superimposed relation, a plurality of clamping members, movable means positioned adjacent the outer sides of said frame for supporting said clamping members in spaced arrangement around said frame, means for connecting said movable means for substantially simultaneous operation of said clamp- I ingrmembers, and means located adjacent one of said movable means for actuating said connecting means.

3. Apparatus as claimed in claim 2 wherein said movable means comprise a plurality of rotatable shafts extending one adjacent each of the outer sides of said frame, said connecting means being located on the adjacent ends of said shafts.

4. Apparatus as claimed in claim 3 wherein said connecting means comprise gear elements for transmitting rotation of one said shaft to the other said shafts, said actuating means comprising a manually operable member for rotating said one shaft.

5. Apparatus for assembling matching sections of shelltype molds comprising a polygonal hollow frame, yieldable means carried by said frame and adapted to engage the outer edge portions of a mold section positioned Within said frame for supporting the same to receive another mold section in superimposed relation, a plurality of rotatable shafts extending one adjacent each of the outer sides of said frame, means for supporting said shafts for rotation relative to said frame, a plurality of clamping members carried on each of said shafts for rotation into and out of overlying relation with said other mold section on said frame, connecting means for the adjacent kends of said shafts and operable for causing substantially simultaneous rotation of said clamping members, and a manually operable member for actuating said connecting means.

6. Apparatus as claimed in claim 5 wherein said connecting means comprise gear elements for transmitting rotation of one of said shafts to the other said shafts, said manually operable member being operable for rotating said one shaft.

7. Apparatus as claimed in claim 6 wherein latching means is provided for retaining said manuallyoperable member in operative position.

8. Apparatus for assembling matching sections of shelltype molds comprising a rotatable support, a plurality of hollow frames mounted on said support, yieldable means carried by each of said frames and each being adapted to engage the outer edge portions of a mold section positioned respectively within said frames for supporting the same to receive another mold section in superimposed relation, a plurality of clamping members, movable means carried by each of said frames for supporting said clamping members in spaced arrangement around each of said frames, means for actuating said movable means to position said clamping members for operative engagement with the outer edge portions of said m-old sections in said superimposed relation, and means for rotating said support for sequentially moving each of said frames to a predetermined position.

9. Apparatus as claimed in claim 8 wherein heating 8 means is provided in a zone adjacent said support whereby rotation of support is effective for moving each of said frames through said zone.

10. Apparatus as claimed inA claim 9 wherein means i provided for moving said heating means away from said support during rotation thereof and thereafter returning the same to initial position.

References Cited in the file of this patent UNlTED STATES PATENTS 935,503 Hetherington Sept. 28, 1909 1,066,278 Hurlbut July 1, 1913 1,592,660 Gilman July 13, 1926 2.069336 Palucki Feb. 2, 1937 2,106,931 Polson Feb. 1, 1938 2,275,854 .Tones Mar. 10, 1942 2,455,055 Gray Nov. 30, 1948 2,624,389 Bungay Ian. 6, 1953 2,728,122 McLeer Dec. 27, 1955 

